Objective:

To analyze the shifting risks of developing subsequent primary cancers (SPCs) among cancer survivors in the US over the past four decades, highlighting the significance of understanding these trends for better patient management.

Key Findings:

• Overall SPC incidence declined by 0.63% annually in women and 0.95% in men, driven by younger survivors, indicating a need for tailored follow-up strategies.
• SPC incidence increased with age at index cancer diagnosis, particularly among those diagnosed at 65 years or older, suggesting a higher risk in older populations.
• Female survivors of lung cancer showed a 1.12% annual increase in SPC incidence, while breast cancer survivors had stable SPC rates across age groups, highlighting the need for different surveillance approaches.
• Cohort effects indicated higher SPC risk among patients born in the early to mid-20th century, which may reflect generational exposure to risk factors.

Interpretation:

The findings suggest that certain subgroups, particularly older cancer survivors and those with specific cancer types, may require targeted surveillance due to increasing SPC risks, emphasizing the need for personalized care.

Limitations:

• The study could not identify specific causes of SPC trends, which limits understanding of underlying mechanisms.
• SEER data lacks information on treatment exposures, genetic factors, and lifestyle behaviors, which could influence SPC risk.
• No adjustments were made for multiple comparisons across subgroup analyses, potentially affecting the reliability of findings.

Conclusion:

Targeted surveillance may benefit specific survivor groups, including female lung cancer and melanoma survivors, as well as older cancer survivors facing increasing SPC risks, underscoring the importance of tailored follow-up care.